T-cell dependence of physiological differences in the response to optic nerve crush injury in EAE-resistant and EAE-susceptible rats. a, Adult Lew and SPD rats, which had undergone thymectomy 1 d after birth, and normal adult control rats were subjected to optic nerve crush, and their RGCs were counted 2 weeks later, as described in Figure 2. Significantly fewer labeled RGCs were seen in the thymectomized SPD rats than in the normal SPD rats (p < 0.01). In Lew rats, the opposite was seen, but the effect was not significant (p> 0.1). b, Lew and SPD rats, thymectomized 1 d after birth, were subjected to contusive injury of the spinal cord at the level of T7 or T9 using the NYU impactor. Sham-operated rats were laminectomized but not contused. After 2 weeks, both sham-operated and contused rats were subjected to optic nerve crush and counting of surviving RGCs, as described in Figure 2. Significantly more labeled RGCs were seen in the preinjured SPD rats than in the sham-operated SPD controls (p < 0.05). In Lew rats, differences in the number of labeled RGCs between the preinjured and the sham-operated rats after optic nerve injury were not significant (p > 0.1). *p < 0.05; **p < 0.01; Student's t test.